Conformational, vibrational and DFT studies of a newly synthesized arylpiperazine-based drug and evaluation of its reactivity towards the human GABA receptor

DFT and MD investigations of the biomolecules of phenothiazine derivatives: interactions with gold and water molecules and investigations in search of effective drug for SARS-CoV-2

Theoretical analyses of two phenothiazine derivatives, 10-[3-(dimethylamino)-2-methylpropyl]phenothiazine-2-carbonitrile (CYM) and 2-[4-[3-(2-chlorophenothiazin-10-yl)propyl]piperazin-1-yl]ethanol (PAZ) are reported using density functional theory (DFT) and molecular dynamics (MD) simulations. Spectroscopic studies, different electronic and chemical parameters are predicted. Red and yellow in electrostatic potential plot is in rings and oxygen atom in PAZ and C≡N and rings in CYM are sensitive to nucleophilic attacks. The blue in hydrogen atoms refer to electrophilic attack in both PAZ and CYM. Stability of the protein-ligand complex formed with these derivatives and angiotensin-converting enzyme 2 (ACE2) was investigated using MD simulation. Radius of gyration of C-alpha atom of 6VW1 displayed the conformational convergence toward a compact structure leading to stable 6VW1-ligand complex which are also in agreement with root mean square fluctuation (RMSF) values. Localized area predicts reactive sites for Au and H₂O molecules interaction with these compounds for further practical applications. Charge density is localized on both molecules and also tries to move toward Au-Au dimer and water molecule and such they are expected to contribute to the sensing performance. Communicated by Ramaswamy H. Sarma.

Molecular structure, spectroscopic, dielectric and thermal study, nonlinear optical properties, natural bond orbital, HOMO-LUMO and molecular docking analysis of (C6Cl2O4) (C10H14N2F)2·2H2O

A new chloranilate compound with 1-(2-fluorophenyl)piperazine has been synthesized and characterized using spectroscopic methods and X-ray diffraction. The atomic arrangement can be described by an H-bonded 3D network, formed by anionic entities, organic cations and H₂O molecules linked together via NH…O, OH…Cl, CH…Cl and CH…O hydrogen bonds. The vibrational absorption bands of the various characteristic groups of this compound have been identified by infrared spectroscopy. Moreover, the thermal and dielectric analyses have shown that the title compound has a phase transition at 393 K. The surface mapped over the d_norm property, highlights the A⋯H (AO, C, Cl and F) as the main intermolecular contacts. On the other hand, the geometry, intermolecular bonds and harmonic vibrational frequencies of the title molecule have been investigated using the B3LYP/6-31G (d, p) method. The stability of the structure obtained, as well as the charge transfer within the molecule, have been confirmed by determining the energies of the HOMO and LUMO levels and the theoretical gap energy. Molecular docking studies of the title compound have also been conducted as part of this study.

One-step solvothermal synthesis of high-emissive amphiphilic carbon dots via rigidity derivation

In nanoscience, amphiphilic carbon dots (ACDs) are of great importance due to their excellent transferability for application in biological sensing, imaging and labelling. However, facile synthetic strategies are still limited, especially for obtaining high-emissive ACDs. Since the development of a high-emissive feature is strongly desired for improving the practical resolution in vivo, here we report a chemical strategy that uses rigid molecules to straightforwardly construct amphiphilic carbon dots (ACDs) with high luminescence quantum yields (QYs). By using 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), a typical coplanar compound, as the only precursor, well-defined ACDs were prepared via a one-step solvothermal process which exhibited a superior QY of up to 29%, largely superior to those prepared from precursors with less rigid structures. The effect can be mainly attributed to a significant suppression of the competition of non-radiative decay through rigidity derivation. Metal ionic doping during the synthesis resulted in a further improvement of the crystallinity and monodispersity of the materials, with retention of the high-emissive ability. This high-emissive photoluminescence behavior of the ACDs is accompanied with an excitation-wavelength dependence, a high biocompatibility and a low toxicity, which together make the ACDs advantageous for application in multi-channel bioimaging.